#include<iostream>
#include<string>
using namespace std;
class Solution {
public:
    bool isPalindrome(string s) {
        int len = s.size();
        string str = "";
        for (int i = 0; i < len; i++) {
            if (s[i] >= 'A' && s[i] <= 'Z') {
                str.push_back(s[i] + 32);
            }
            else if (s[i] >= 'a' && s[i] <= 'z') {
                str.push_back(s[i]);
            }
            else if (s[i] >= '0' && s[i] <= '9') {
                str.push_back(s[i]);
            }
        }
        int left = 0;
        len = str.size();
        int right = len - 1;
        int flag = 1;
        while (left < right) {
            if (str[left] != str[right]) {
                flag = 0;
                break;
            }
            left++;
            right--;
        }
        return flag;
    }
};
int main() {
    double n = 42;
    cout << ((n + 10) / 2) * 6.725 << endl;
    return 0;
}